TIFF 17: Lady Gaga delivers at TIFF with premiere of Gaga: Five Foot Two documentary

That would be Lady Gaga, who gave an intimate one song performance before the screening of her documentary, Gaga: Five Foot Two, at the Princess of Wales Theatre on Friday night.

“How are you doing tonight?” said the singer, who earlier performed two sold-out shows in Toronto at the Air Canada Centre on Wednesday and Thursday night.

“A big thank you to the festival and a big thank you to Chris (Moukarbel) my director.”

Dressed in a pink coat and black vinyl pants, Gaga performed Bad Romance alone on black piano on the stage before her warts-and-all documentary was screened to a packed house.

“I don’t even know what to say,” said an impressed TIFF artistic director Cameron Bailey after Gaga's performance.

The documentary sees Gaga talking about Madonna’s “reductive” comment — she just wishes she had told her to her face and not through the media - and the Mother Monster even has a few meltdowns in the film, specifically during the filming of American Horror Story and while rehearsing for her Super Bowl half-time performance.

But there’s also a very tender side to Gaga, who breaks down into tears while her chronic pain — complications from a broken hip and other maladies — is tended to by a team of massage therapists and doctors.

Moukarbel also spoke from the stage before the screening and thanked Gaga “letting me into your world. I’ve never seen such a mix of power and vulnerability.”